fIlia mea is certainly in the nominative case and is therefore the subject of the verb laudat. So you have (in English) "My daughter always praises....what?. Well, since sapientiam amIcArum is in the accusative it is the object of the verb (it receives the action). You have been led astray by the concept of apposition. It doesn't apply here since there is no other noun phrase in the nominative. You may be confused about the function of laudat. While a conjugated verb may stand alone and suggest its subject, you have an explicit subject here: fIlia mea.